What any one person can do is limited by the power they have. That works for criminally unbalanced people as much as anyone else. But the power one person can have is related to the type of machine they can carry.

After the elementary school shootings in Newton, Connecticut that left 20 children and 6 adults dead, old cultural debates reignited and a familiar parade of protestations began making their way around. It happened because we don’t have prayer in schools. It happened because we have too many guns. It happened because we deinstitutionalized the mentally ill. It happened because of violence in movies and video games. Straw men are popping up all over.

Setting aside the heated rhetoric and the understandable grief-laden anger, there are some facts that should be taken into account. It is true that something was wrong with the man that murdered those innocent people—whether mental, moral, or a combination of the two. It is also true that guns don’t cause death by themselves—they must be used. However, one more thing needs acknowledging—not a moral judgment but a simple physical fact.

According to media reports, the guns that Adam Lanza used to kill 26 people included a semiautomatic Bushmaster .223 rifle that weighed just a few pounds but fires bullets at 3,000 ft/second, has 30 capacity clips, fires instantly with each trigger pull, and can shoot as many as 6 bullets per second. That gun is not responsible for killing those children. Adam Lanza is. However, Lanza needed something like that gun to kill at such a magnitude. A club, a knife, or a musket would not have given him the power he had.

There is a general tendency in the development of technology—machines shrink in size but we can pack more and more power into those smaller volumes. We see this in mobile phones that can out-compute yesteryear’s giant mainframes. We see this in terrorists’ wearable bombs that can out-damage yesteryear’s tanks. Think about tiny weaponized smallpox vials or nuclear suitcases and the danger is even more stark.

With terrorists, there is still at least the need for some level of expertise and typically some difficulty in gathering materials. Guns, however, are ready-made and easily acquired. The technological changes over the 221 hundred years since the 2nd Amendment ensured the right to bear arms means that the rule originally applied to single-shot weapons using muzzles and flintlocks now applies to rifles that can fire 30 rounds in a few seconds and be quickly reloaded by switching clips.

We have to deal with these technological changes. In 1791, one man couldn’t kill 26 people in a few seconds with a device you could receive in the mail.

Some people want to redirect the conversation away from guns altogether to the state of the mental health system. No doubt that system could be improved. But think about the numbers. No matter how much we improve our mental health system (realistically) we will not be able to cure or restrain everyone who might go on a killing spree. That’s not a case of the perfectionist fallacy—the faulty claim that since we can’t make a policy perfect we might as well do nothing. That’s a case of realizing that the smaller and more powerful technology becomes, the more dangerous and devastating the effect of the few that slip through the cracks in the system. One man who slips through the cracks of an imperfect system won’t be able to kill 17 or 26 or 35 people at a distance in a few minutes with a knife. But if he gets a semiautomatic rifle he can. The smaller and more powerful available technology becomes, the exponentially more dangerous a mental health system’s imperfections become.

The problem reminds me of a passage from Robert J. Sawyer’s novel, Calculating God. An extraterrestrial scientist named Hollus gives one reason why so very few advanced civilizations have been encountered in the galaxy even though Drake statistics suggest there should be many.

“I am given to understand that many humans suffer from mental problems…As do [we]. It is another concern: as technology advances, the ability to destroy the entire race becomes more accessible. Eventually, it is in the hands not just of governments, but also individuals—some of whom are unbalanced.”

That was a staggering thought. A new term in the Drake equation: f-sub-L, the fraction of members of your race who are loony.

In the novel the case was extreme—the extinction of entire species. But the issue raised is the same. Small, powerful, technology is not itself evil, but it gives people would do great evil the ability to actually do it.

The question we are faced with then is this: How much destructive power are we willing to risk letting one person get a hold of?